There are now several patent specifications showing different forms of friction spinning apparatus in which fibres are spun into a yarn by being deposited on and twisted by a moving perforated surface. The surface generally is formed by a hollow perforated roller or base member. However, the only specification which gives details of the structure of the roller and its surface is U.S. Pat. No. 4,281,507 of Vyzkumny Ustav Bavlnarsky. This shows various formations of perforations or holes in the surface and mentions that the base member can be coated, with several possibilities for coatings being given. Other patents show the roller and its surface only schematically and none has yet formulated the requirements for a perforated surface of this kind.